Computer System and Bandwidth Control Method for the Same

1. A bandwidth control method in a computer system including a plurality of computers that share a storage apparatus, comprising the steps of: assigning, by a first computer of the plurality of computers, priorities to access requests received from a client computer connected to the computer system, the priorities being based on an attribute of the client computer; determining a bandwidth for use with the storage apparatus through an exchange of information about the priorities with a rest of the plurality of computers; transmitting each of the access requests to the storage apparatus based on the determined bandwidth, wherein the step of determining the bandwidth includes deriving an accumulated priority value by adding the priorities assigned to the received access requests and exchanging the accumulated priority value of the first computer with accumulated priority values derived by the rest of the plurality of computers; calculating, by the first computer, a ratio of the accumulated priority value for the first computer to a total accumulated priority value derived by adding the accumulated priority value for the first computer to the accumulated priority values of the rest of the plurality of computers; and determining the bandwidth for use with the storage apparatus in accordance with the ratio.

2. A bandwidth control method according to claim 1 , wherein priority is determined based on information specifically about the attribute of the client computer.

3. A bandwidth control method according to claim 2 , wherein the information specifically about the attribute of the client computer is stored in each of the plurality of computers.

4. A bandwidth control method according to claim 2 , wherein the information specifically about the attribute of the client computer is stored in the storage apparatus, and each of the plurality of computers reads the information specifically about the attribute of the client computer from the storage apparatus.

5. A bandwidth control method according to claim 1 , wherein the first computer exchanges the information about the priorities with the rest of the computers over a network connecting the plurality of computers.

6. A bandwidth control method according to claim 1 , wherein the first computer exchanges the information about the priorities with the rest of the computers via the storage apparatus.

7. A bandwidth control method according to claim 2 , wherein the information specifically about the attribute of the client computer includes the information about the priorities corresponding to an IP address of the client computer, an access operation, or an accessing file, and the first computer performs priority assignment based on the information specifically about the attribute of the client computer.

8. A bandwidth control method according to claim 1 , wherein the storage apparatus is plurally provided.

9. A bandwidth control method according to claim 1 , wherein the storage apparatus is an NAS (Network-Attached Storage).

10. A computer system, comprising: a first computer; a second computer connected to the first computer; and a storage apparatus connected to both the first computer and the second computer, wherein the first computer and the second computer assign priorities to access requests received from a client computer connected to the first computer, the priorities being based on an attribute of the client computer, wherein the first computer receives information about the priorities assigned by the second computer, wherein the first computer determines a bandwidth for use with the storage apparatus by using the received information about the priorities assigned by the second computer and information about the priorities assigned by the first computer, wherein the first computer transmits the access requests to the storage apparatus based on the determined bandwidth, wherein the first computer determines bandwidth by deriving an accumulated priority value by adding the priorities assigned to the received access requests, and exchanges the accumulated priority value of the first computer with an accumulated priority value derived by the second computer, and wherein the first computer determines a total accumulated priority value by adding the accumulated priority value received from the second computer and the accumulated priority value of the first computer, calculates a ratio of the accumulated priority value of the first computer to the total accumulated priority value, and determines the bandwidth for use with the storage apparatus in accordance with the ratio.

11. A computer system according to claim 10 , wherein priority is determined based on information specifically about the attribute of the client computer.

12. A computer system according to claim 10 , wherein the information specifically about the attribute of the client computer is stored in the storage apparatus, and each of the first computer and the second computer reads the information specifically about the attribute of the client computer from the storage apparatus.

13. A computer system according to claim 10 wherein the first computer exchanges the information about the priorities with the second computer over a network connecting the first computer and the second computer.

14. A computer system according to claim 10 , wherein the information specifically about the attribute of the client computer includes information indicating that when the client computer asks the first computer to execute an online job, an access request relative to the online job is assigned a high priority, and wherein when the client computer asks the first computer to execute a batch job, an access request relative to the batch job is assigned a low priority.

15. A computer system according to claim 10 , wherein the information specifically about the attribute of the client computer includes information indicating that when the client computer asks the first computer to execute a data reading process, an access request relative to the data reading process is assigned a low priority, and wherein when the client computer asks the first computer to execute a data writing process, an access request relative to the data writing process is assigned a high priority.

16. A computer, comprising: a control section; a first connection section connected to a storage apparatus for sharing among other computers; a second connection section connected to the other computers; a third connection section connected to a client computer; and memory, wherein the control section assigns priorities to access requests received from the client computer via the third connection section based on specific information, and stores the priorities assigned to the access requests in the memory, receives information about the priorities of the other computers, wherein the control section, based on the information about the priorities of the other computers and information about the priorities assigned to the access requests stored in the memory, determines a bandwidth for use with the storage apparatus, and based on the determined bandwidth, transmits the access requests to the storage apparatus via the first connection section, wherein the control section determines the bandwidth by deriving an accumulated priority value for the computer by adding the priorities assigned to the received access requests and exchanging the accumulated priority value with accumulated priority values derived by the other computers, wherein the control section calculates a ratio of the accumulated priority value for the computer to a total accumulated priority value derived by adding the accumulated priority value for computer to the accumulated priority values of the other computers, and wherein the control section determines the bandwidth for use with the storage apparatus in accordance with the ratio.

17. A computer, comprising: a first computer; a second computer connected to the first computer; and a storage apparatus connected to both the first computer and the second computer, wherein the first computer and the second computer assign priorities to access requests received from a client computer connected to the first computer, the priorities being based on information specifically about an attribute of the client computer, wherein the first computer receives information about the priorities assigned by the second computer, and determines an accumulated priority value by adding the priorities assigned to the received access requests, and exchanges the accumulated priority value of the first computer with an accumulated priority value derived by the second computer, wherein the first computer determines a total accumulated priority value by adding the accumulated priority value received from the second computer and the accumulated priority value of the first computer, calculates a ratio of the accumulated priority value for the first computer to the total accumulated priority value, and determines the bandwidth for use with the storage apparatus in accordance with the ratio, wherein based on the determined bandwidth, the first computer transmits the access requests to the storage apparatus, wherein the information specifically about the attribute of the client computer includes information indicating that when the client computer asks the first computer to execute a data reading process, an access request relative to the data reading process is assigned a low priority, wherein when the client computer asks the first computer to execute a data writing process, an access request relative to the data writing process is assigned a high priority, wherein the information specifically about the attribute of the client computer includes information indicating that when the client computer asks the first computer to execute an online job, an access request relative to the online job is assigned a high priority, and wherein when the client computer asks the first computer to execute a batch job, an access request relative to the batch job is assigned a low priority.